1. Field of the Invention
The present invention relates to a heat sink package in which a semiconductor package and a heat sink are bound to each other and a method of fabricating the same.
2. Description of the Related Art
Generally, a semiconductor package is prepared by mounting a single or a plurality of semiconductor chips on a chip pad in a lead frame, and sealing the chips using a molding member such as epoxy molding compound (EMC) to protect the inside of the semiconductor package, and the semiconductor package is mounted on a printed circuit board (PCB) substrate. Recently, as electronic devices have increasingly been made with high speed, large capacity and high integration, there is a need to achieve small sized, inexpensive and light weight power devices applied to automobiles, industrial machinery and home appliances.
Power devices such as a silicon-controlled rectifier (SCR), a power transistor, an insulated-gate bipolar transistor (IGBT), a metal oxide semiconductor (MOS) transistor, a power rectifier, a power regulator, an inverter, a converter, and a combination thereof are designed to operate at a voltage in the range of 30 to 1000 V or greater. Such power devices are distinguished from conventional logic or memory devices that operate at a high voltage, and thus a semiconductor package for power devices needs to have superior heat discharging capability for discharging heat generated from the power devices and insulating properties for operating at a high voltage.
Generally, in order to discharge heat generated from power devices, a heat sink is assembled on a semiconductor package as disclosed by Fairchild Semiconductor Corporation in Korean Patent Application No. 2007-20564.
FIG. 1 is an exploded perspective view of a conventional semiconductor package for power devices 10 and a heat sink 30.
Referring to FIG. 1, a heat sink 30 formed of a metallic material may be attached to a semiconductor package for power devices 10. The heat sink 30 is assembled to a semiconductor package for power devices 10 by a bolting member 20 that passes through a bolting hole 10h of the semiconductor package for power devices 10.
Typically, a resin-based material used for a transfer molding process, such as an epoxy molding compound (EMC) is used as a molding member 10a forming the external shape of a semiconductor package for power devices. Since the semiconductor package for power devices 10 can be simply and economically fabricated using such a resin-based material, the resin-based material is applied to various fields. However, when the heat sink 30 and the semiconductor package for power devices 10 are assembled by the bolting member 20, cracks and warpages may be induced in the molding member 10a due to compressive stress and shear stress applied to the surface of the semiconductor package for power devices 10 by the bolts.
Such cracks and warpages may provide a moisture absorbing passage in the semiconductor package for power devices 10 or destroy insulation so that reliability or lifetime of the power devices may be decreased.
In addition, an insulation sheet and/or a thermal grease is generally interposed between the semiconductor package for power devices 10 and the heat sink 30. However, the insulation sheet and/or the thermal grease may increase thermal resistance so that reliability or lifetime of the power devices may be decreased.